The present invention relates to a new and improved turbine engine component and the method by which it is made. Specifically, the present invention relates to a turbine engine component having a plurality of airfoils disposed in an annular array between inner and outer shroud rings.
Turbine engines commonly include a stator which is having airfoils or vanes which direct a flow of high temperature gases against the blades of a rotor. In order to withstand severe operating conditions, it has been suggested in U.S. Pat. No. 4,464,094 that turbine engine components could be constructed with airfoils having either a single crystal or columnar grained crystallographic structure. The airfoils shown in this patent extend between shroud rings having single crystal or columnar grained crystallographic structures with a growth direction transverse to the leading and trailing edges of the airfoils.
In U.S. Pat. No. 4,464,094, the shroud rings are cast in segments separately from the airfoils. The airfoils are then connected to the shroud ring segments by a brazing operation. In U.S. Pat. Nos. 4,008,052 and 4,195,683, molten metal is solidified around end portions of preformed airfoils.
In order to minimize thermal stresses in turbine engine components, it has been suggested in U.S. Pat. No. 3,075,744 that the outer ends of the airfoils be movable relative to an outer shroud ring to accommodate thermal expansion of the airfoils. The inner ends of the airfoils are anchored to an inner shroud ring. The outer ends of the airfoils are connected with the outer shroud ring at slip joints.